This project studies the relationship between lead exposure and academic achievement in college students. Most studies of the neurobehavioral effects of lead have focused on performances at the low end of the distribution. There is evidence that lead affects outcome across the entire distribution. This is a retrospective cohort study of subjects whose cognitive function is adequate to gain admission to college. We will use x-ray fluorescence to measure bone lead concentrations in undergraduate college students and test the hypothesis that achievement scores are related to early lead exposure. Early lead exposure has been shown to have measurable effects on academic performance and neurobehavioral outcomes at 18 years of age. Should an effect be found in this study, the spectrum of lead toxicity would be expanded to include subjects with above average function.